Tool connection units for earth working machinery



April 26, 1966 G. EYLER ETAL 3,247

TOOL CONNECTION UNITS FOR EARTH WORKING MACHINERY Filed April 7, 1964 4 Sheets-Sheet l INVENTORS fieoz-yeig zew April 2%, WW G. EYLER ETAL. 3,247,%

TOOL CONNECTION UNITS FOR EARTH WORKING MACHINERY Filed April '7, 1964 4 Sheets-Sheet 2 INVENTORS fieaa ya figfiwm April 1966 G. EYLER ETAL 3,2473% TOOL CONNECTION UNITS FOR EARTH WORKING MACHINERY Filed April 7, 1964 4 Sheets-Sheet 5 INVENTORS George figfiww $272222: 6- Edfiwg 49522222272 Z'flwdfig April 2%, 1966 e. EYLER ETAL 334K986 TOOL CONNECTION UNITS FOR EARTH WORKING MACHINERY Filed April '7, 1964 4 Sheets-Sheet 4 INVENTORS G 60 Wye 96 82 United States Patent Ofitice 3,247,986 TOUL CDNNECTION UNITS FOR EARTH WORKING MACHINERY George Eyler and William G. Easley, iampa, Ten, and William T. Braly, Albuquerque, N, Merc, assignors, by mcsnc assignments, to Hamischfeger Corporation, Milwaukee, Wis, a corporation of Wisconsin Filed Apr. 7, 1964, Ser. No. 357,881 7 Claims. (Cl. 214-138) This invention relates to earth moving or excavating machines such as power shovels, loaders, trenchers, back hoes and the like. More particularly, it is concerned with an improved connection unit or linkage head between the working tool of such a machine and the extended working arms or elements by means of which the working tool is manipulated and applied to the work at hand.

The representative back hoe or earth working machine of the type contemplated for improvement in accordance with this invention carries on its main chassis or base some sort of movable carriage or turntable which is usually rotatable about a vertical axis. On said carriage or turntable is mounted some sort of extended boom and/or carrier arm(s) for the operating tool and associated parts including control elements such as cables and/or hydraulically activated pistons, etc. In many cases, the operating tool, e.g. a bucket, shovel, scoop, or ripper claw, is pivotally mounted at one end of a dipper stick or secondary arm which, in turn, at a point substantially removed from its tool end, is pivotally connected to the main boom.

Almost without exception the pivotal mounting of the tool on the dipper stick has heretofore been such that the only motion which could beimparted to the tool relative to the dipper stick was a swinging or pivotal type motion (in the same plane as the dipper stick) about an axis fixed in orientation relative to the dipper stick (usually an axis running transversely substantially at right angles to said dipper stick). Accordingly, variations in the transverse attitude or position of the tool as it is applied to the work at hand have not generally been attainable in such equipment except by movement of the entire machine. Most of those efforts which have been directed towards providing more convenient adjustability in this respect have resulted in the modification of existing elements of the machine, such as by providing for rotation of the boom or dipper stick about its own axis. However, changes in tool orientation permitted thereby are not independently achievable since such rotations inherently cause concomitant changes in the direction and course of travel transmitted to the tool by the boom and dipper stick assembly.

In U.S. Patent 2,725,996 to P. F. Britton, it is proposed to provide for additional adjustment in the orientation of a digging tool in such machinery by interposing a separate head between the tool and the dipper stick. Although this approach has the advantage of permitting changes in tool orientation without necessarily changing the action or direction of the stroke delivered by the boom and dipper stick assembly, the particular head disclosed in said Britton patent cannot be relied upon to hold the tool at a given predetermined tilt or angle to the horizontal throughout a full working stroke of the machine since said head is subject to slippage due to the back torques applied to the tool by the uneven stresses which are inevitably encountered across same in actual earth working operations.

The primary object of the present invention is to provide more versatile earthworking and material moving apparatus which is especially adapted to perform a wide variety of operations efliciently.

Another object is to provide such apparatus in which 3,247,936 Patented Apr. 26, 11966 the earth working and material moving implements can conveniently be set at any desired operative angle relative to the work at hand without the necessity of changing the position of the entire apparatus or affecting the orientation or motion of the working arms.

Another important object of the invention is to provide hydraulically actuated means for controlling and adjusting said operative angle setting of the working tool which means operates in such a way as to preclude accidental changes or uncontrolled variations in said setting during operation of the apparatus, such as might otherwise be caused by the working stresses against the tool.

Other objects and advantages of the invention will be obvious or will appear during the course of the following description.

The above objects are accomplished in accordance with the present invention by providing a tool holding connection unit or head including a body portion designed for pivotal linkage with a dipper stick and/or other manipulative arms of earth working machinery and, rotatably mounted on said body portion, a heavy plate designed for readily attaching a digging tool thereto, the drive means provided for said rotatable plate being a hydraulically actuated system which also inherently or automatically prevents rotation of said plate and holds same at a fixed rotational position whenever the rotatable plate is not being actively driven by the hydraulicsystern. Preferred embodiments of our invention are described hereinafter in conjunction with the accompanying drawings in order to assist the reader in obtaining a full understanding of the invention and methods of actually practicing same.

In the drawings, FIGURE 1 is a fragmentary side view of the back hoe bucket linked to the dipper stick of the machine by means of a connection unit or head constructed in accordance with our invention;

FIGURE 2 is an enlarged side view of the connection unit of FIGURE 1 with most parts shown in section;

FIGURE 3 is a partly cut away and sectional view along line 3-3 of FIGURE 2;

FIGURE 4 is an enlargement of a portion of a sectional cut along line 44 of FIGURE 3 through the interlocking brake elements and showing details of their construction as seen at the time of full engagement;

FIGURE 5 is a partly cut away top plan view of another type of connection unit characterized by a simpler hydraulic system; and

FIGURE 6 is a largely sectional view of the unit of FIGURE 5 taken along line 6-6 thereof with a fragment of the back wall of the housing cut away to show the position of the hydraulic motor.

Referring now to the drawings and particularly to FIGURES l and 2, bucket 10 having digging edge 12 is pivotally joined through connection unit 14 to dipper stick 16 of a back hoe or similar earth working machine. The conventional swinging motion of the bucket (so that a given point thereon describes essentially an arc in a substantially vertical plane) is provided by means of pivot pin joint 18 between the dipper stick 16 and the connection unit 14 and parallel pivot pin joint 20 between the connection unit 14 and piston rod 22 of double acting hydraulic cylinder 21, which in turn is pivotally joined at its other end to the dipper stick 16 at a higher point thereon (not shown).

In order to permit greater variation and control over the attitude of the bucket relative to the work at hand, the heavy plate member 24 to which the bucket or other tool is attached is rotatably mounted, by means of integrally connected shaft 26 in the main body 25 of the connection unit 14. Rotation of the heavy plate member 24 and shaft 26 is accomplished by reversible hydraulic motor 30 and suitable gearing such as pinion gear 32 and matching gear teeth 28 on the outside of plate member 24. Alternatively, plate member 24 could be attached to an internal ring gear running around the outside of a pinion gear such as 32. To insure satisfactory operation, the housing 34 for shaft 26 includes a suitable heavy duty bearing assembly 36 made up of roller bearing 35 and bushing 37. It will be seen that, by actuating hydraulic motor 30, the position and orientation of the bucket can be easily varied and changed as desired independently of the action of the boom and dipper stick or the rotating action inducible by operation of hydraulic cylinder 21, so as to provide greater freedom of manipulative control by the operator in applying the tool to the work at hand.

A key feature of the present invention is the inclusion in the drive system of reversible hydraulic motor 30 of inherent means to prevent uncontrolled rotation or slippage due to working' stresses encountered by the tool during actual operation, thus insuring that the position of said tool can at all times be under the positive control of the operator. The embodiment of the invention shown in FIGURES l and 2 achieves this key objective by providing between the rotatable plate member 24 and the stationary body 25 of the connection unit a normally engaged, but readily disengageable and re-engageable, brake means capable, when engaged, of locking the two parts together. As will be explained shortly, the disengagement and re-engagement actions are provided as an integrated part of the main hydraulic system of motor 30 so that said brake means is disengaged only when the hydraulic motor 30 is positively activated by the operator. As shown best in FIGURE 2, such brake means between plate 24 and main body 25 can most conveniently be provided in the form of respective cooperating portions 38 and 38' which are concentrically located with respect to shaft 26 so that they are readily and fully engageable at virtually any position of rotation of plate 24. Although concentric or ring-shaped elements 38 and 38' may take various brake-type or clutch-type engaging forms, including high friction grips providing sufiicient resistance to torsional slippage, it is preferred that said elements be capable of a more positive engagement.

For example, as shown in FIGURES 3 and 4, elements 38 and 38 can present on their directly opposed adjacent surfaces a regular pattern of substantially radially extending ribs or fine ridges 39 and 39' designed to intermesh with one another as shown, thereby positively locking together the respective parts of the apparatus on which they are located.

It will further be seen from FIGURE 2 that complete, intermeshing engagement of elements 38 and 38' is normally effected by providing a continuously applied thrust in an axial direction along shaft 26 by means of springs 40 acting against compression nut 42 which is threaded onto shaft 26. A lock ring 43 may be used with advantage to prevent any accidental gradual change in position of compression nut 42 during operation of the unit. Obviously, a single large coiled spring could be used in place of the series of small springs 40 actually shown in FIGURE 2.

The hydraulic system which actuates hydraulic motor 30 is integrally connected to the housing 34 in such a way that, whenever motor 30 is being hydraulically driven in either direction, the hydraulic fluid will simultaneously enter housing 34 through connection 46 and exert its full pressure upon piston 44, which is provided with seal rings 41, 45 and 47. The resulting force upon piston 44 is transmitted through thrust bushing 48 to the shaft 26 and is sufficient to overcome the force exerted by springs 40, thereby causing shaft 26. and heavy plate 24 to move downwardly sutficiently to disengage elements 38 and 38' so that shaft 26, plate 24 and associated parts 4 are free to rotate when, but only when, the operator actively actuates hydraulic motor 30. It will be noted that piston 44 is restrained from rotation by means of a vertical groove 49 on one side of the lower portion thereof and a dog point plug 50 which extends through the housing 34 and into groove 49.

The hydraulic system which controls the operation of connection unit 14 will be better understood from the following explanation of the details thereof in connection with the layout shown in FIGURE 2. The hydraulic fluid connections to the reversible motor consist of a front connection 52 which is joined to conduit 54 through fitting 53 and a rearward connection 56 (hidden behind fitting 53) which is joined to conduit 58. Conduits 54 and 58 lead through T-fittings 60 and 64 respectively to flexible conduits 62 and 66 respectively. Flexible conduits 62 and 66 are in turn interchangeably connected by a suitable control valve(s) (not shown) to a hydraulic pump (not shown) and the reservoir (not shown) from which the hydraulic fluid is fed to the inlet of the pump. Thus, by suitable manipulation of the controls, the hydraulic fluid can be forced through hydraulic motor 30 in either direction, thereby driving gear 32 and causing the tool mounting plate 24 and any tool connected thereto to rotate in either direction on shaft 26. The remaining end of each of the fittings 64 and 60 is joined to connection 46 leading to housing 34 by means of T fitting 68, which is made to serve as a double check valve by inserting sliding plug 67 inside the horizontal bore of same before fittings 63 and 65 are connected thereto. Both ends of sliding plug 67 are essentially conical in shape so that pressurized hydraulic fiuid supplied to hydraulic motor 30 through either T 60 or T 64 will automatically force sliding plug 67 to block the fluid from passing through the horizontal bore of T 68 and divert said fluid instead into connection 46 leading to housing 34. Thus, regardless of the direction of rotation, whenever reversible hydraulic motor 30 is actuated, the integrated hydraulic system of the unit will automatically inactivate or release the interlocking braking action between elements 38 and 38.

This advantageous key feature of avoiding uncontrolled movement or slippage in the rotatable connection unit of this invention can also be attained without dependence upon interlocking brake means between plate member 24 and the body 25 of the connecting unit. For example, in FIGURES 5 and 6 there is illustrated an embodiment of this invention incorporating a drive system which is essentially self-locking or inherently resistant to slippage caused by back torque on the working tool. This particular system employs a single-thread worm 70 as the drive gear and a worm wheel 72 as the driven gear. Ideally, the worm is of cone or hour-glass form as shown so as to minimize wear. The worm is of relatively small diameter compared to the worm wheel providing a mechanical advantage of about 30/1. Because of this high mechanical advantage and more especially because of the small lead angle of the thread 76 of worm 70, reverse torque on the working tool transmitted to the worm 70 through worm wheel 72 does not result in rotation of the worm 70 so that back slippage is inherently avoided and the need for separate braking means is obviated.

Referring to FIGURES 5 and 6 in more detail, FIG- URE 5 is a top plan view of the unit in which part of the top of the gear housing 71 has been cut away to show the worm 70 suitably mounted at each end by means of roller thrust bearings 73 and 75, which are shown in cross-section taken at the mid-height thereof. FIGURE 6 is a side view of the unit of FIGURE 5 taken along line 66 thereof and largely in section and with portions of the drive gear housing walls cut away to show the mounting plate and hydraulic connections of the hydraulic motor 30 in the rear. This reversible hydraulic motor 30 is connected directly to worm 70 by means of a suitably mated and/or keyed shaft (not shown). The thread 76 on worm 70 mates with teeth 77 on worm wheel 72. Worm wheel 72, in turn, is keyed onto shaft '78 which is rotatably mounted in radial roller bearings 79 and 81.

In this case, the tool mounting plate 24 is splined onto the end of shaft 78 and bolted to the mounting flange 19 of the tool. Each end of shaft 78 is also threaded so that hold-on nuts 80 and 82 can be applied and used to adjust the position of shaft 78 and worm wheel 72 and also to maintain pressure on oil seals 83 and 85.

It will be noted that in this case the hydraulic sys tem is somewhat simpler than in the embodiment of FIGURES 1 and 2, since in FIGURES 5 and 6 it is merely necessary to reverse the flow of hydraulic fluid from the pump (not shown) between fittings 53 and 56 on the hydraulic motor using a simple control valve (not shown) in order to reverse the direction of rotation of the rotatable connection unit.

In addition to a worm and worm wheel drive as depicted in FIGURES 5 and 6, other types of rotation drives are available which will be self-locking against back thrust when the hydraulic drive system is inactivated and can therefore be employed in the rotatable connection unit of this invention. For example, a set of helical gears on non-parallel shafts could be used for this purpose.

Other variations in size, shape, and arrangement of parts are, of course, possible with our invention as will be obvious to those skilled in the art. Accordingly, the particular embodiments of the invention described herein are merely designed to provide preferred examples of the practice of our invention and are not to be construed as limiting the scope of the invention which is defined only by the appended claims.

Having fully described the principles of our invention and preferred embodiments thereof, what we claim and desire to secure by US. Letters Patent is:

1. A hydraulically actuated tool connector for use in powered earth working and materials handling machinery, such as backhoes, diggers, graders and loaders, compris- (a) a body portion having connection means suitable for pivotal attachment to the working arms of such powered apparatus and providing at least two pivotal connection points with axes of rotation that are separated but parallel;

(b) a main shaft rotatably housed in said body portion with an axis of rotation substantially perpendicular to said separate, parallel axes of rotation;

(c) a heavy plate member mounted on said main shaft so as to rotate integrally therewith while carrying the working tool of said powered machinery;

(d) a reversibly rotatable, hydraulically driven motor mounted on said body portion and having positive drive means to said rotatable shaft and plate member; and

(6) means coordinated with said hydraulically driven motor so that rotation of said shaft and plate member is inherently prevented however said hydraulic motor is not being driven, thereby preventing uncontrolled variations in the position of the working tool during actual operation of the machinery, said means comprising a concentric element on each of said plate member and said main body, said elements having directly opposed intermeshing ribs for positive locking together when said motor is not driven but which ribs are separable when said motor is driven.

2, A hydraulically actuated tool connector as described in claim 1 in which there is provided stresses on the tool and which automatically disengages said means whenever the hydraulic motor is being driven in either direction.

3. The hydraulic tool connector of claim 1 in which said elements are, respectively, on the upper face of said heavy plate member and on the immediately opposite face of said body portion, and spring elements are incorporated in the rotatable housing of said shaft in said body portion which housing includes heavy duty bearing assemblies permitting limited axial movement of said shaft.

4. The hydraulic tool connector of claim 3 in which the rotatable housing of said shaft in said body portion includes means for applying hydraulic pressure thereto suflicient to overcome the loading force of said spring elements and control means assuring that said hydraulic pressure is applied whenever said hydraulic motor is being driven.

5. The hydraulic tool connector of claim 4 in which said means for applying said hydraulic pressure comprises a suitable connection to the hydraulic system of said motor.

6. The hydraulic tool connector of claim 5 in which said connection to the hydraulic system of said motor comprises valve means assuring access to the pressurized side of said hydraulic system regardless of the direction in which said motor is being driven.

7. The hydraulic tool connector of claim 6 in which said valve means comprises a sliding-plug, double check valve in a horizontal passage between the fluid lines to each side of the hydraulic motor which passage has open communication with the housing in which said rotatable shaft is mounted.

References Cited by the Examiner UNITED STATES PATENTS 2,599,677 6/ 1952 Waguespack.

2,725,996 12/ 1955 Britton.

3,027,026 3/1962 Couquet 214138 3,033,394 5/1962 Kashergen 214l38 HUGO O, SCHULZ, Primary Examiner. 

1. A HYDRAULICALLY ACTUATED TOOL CONNECTED FOR USE IN POWERED EARTH WORKING AND MATERIALS HANDLING MACHINERY, SUCH AS BACKHOES, DIGGERS, GRADERS AND LOADERS, COMPRISING: (A) A BODY PORTION HAVING CONNECTION MEANS SUITABLE FOR PIVOTAL ATTACHMENT TO THE WOKING ARMS OF SUCH POWERED APPARATUS AND PROVIDING AT LEAST TWO PIVOTAL CONNECTION POINTS WITH AXES OF ROTATION THAT ARE SEPARATED BUT PARALLEL; (B) A MAIN SHAFT ROTATABLY HOUSED IN SAID BODY PORTION WITH AN AXIS OF ROTATION SUBSTANTIALLY PERPENDICULAR TO SAID SEPARATE, PARALLEL AXES OF ROTATION; (C) A HEAVY PLATE MEMBER MOUNTED ON SAID MAIN SHAFT SO AS TO ROTATE INTEGRALLY THEREWITH WHILE CARRYING THE WORKING TOOL OF SAID POWERED MACHINERY; (D) A REVERSIBLY ROTATABLE, HYDRAULICALLY DRIVEN MOTOR MOUNTED ON SAID BODY PORTION AND HAVING POSITIVE DRIVE MEANS TO SAID ROTATABLE SHAFT AND PLATE MEMBER; AND (E) MEANS COORDINATED WITH SAID HYDRAULICALLY DRIVE MOTOR SO THAT ROTATION OF SAID SHAFT AND PLATE MEMBER IS INHERENTLY PREVENTED HOWEVER SAID HYDRAULIC MOTOR IS NOT BEING DRIVEN, THEREBY PREVENTING UNCONTROLLED VARIATIONS IN THE POSITION OF THE WORKING TOOL DURING ACTUAL OPERATION OF THE MACHINERY, SAID MEANS COMPRISING A CONCENTRIC ELEMENT ON EACH OF SAID PLATE MEMBER AND SAID MAIN BODY, SAID ELEMENTS HAVING DIRECTLY OPPOSED INTERMESHING RIBS FOR POSITIVE LOCKING TOGETHER WHEN SAID MOTOR IS NOT DRIVE BUT WHICH RIBS ARE SEPARABLE WHEN SAID MOTOR IS DRIVEN. 